ISLAMABAD, Pakistan — A car bomb exploded outside the Danish Embassy in an upscale area of the Pakistani capital Monday, killing at least six people, according to reports from hospitals.

A senior official at the Interior Ministry, Rehman Malik, said one foreigner was among the dead, but he did not give a nationality. Casualty lists posted at two hospitals said that six people had died and more than 20 had been injured. Malik said police were investigating whether the blast was a suicide attack.

There was no immediate claim of responsibility for the attack.

The bomb was the second effort to target foreigners in Islamabad in the last few months and came as the civilian government has signed a series of peace deals with Islamic militants in the nation”s tribal areas.

The blast, heard around the city at about 1 p.m. local time, left a deep crater outside the embassy and badly damaged the exterior of the building in an area that has many diplomatic residences, schools and a nearby shopping center. The bomb left a trail of wrecked cars parked in the neighborhood and smashed the facades of nearby houses.

Several European bomb experts who examined the blast site said that the bomb appeared to have contained about 50 kilograms of explosives and created a crater about a meter deep.

A nearby building housing the U.N. Development Program was seriously damaged and a Brazilian woman employed by the U.N. agency was reported to have been badly injured.

The attack Monday was the first time that a foreign embassy had been targeted in Islamabad in recent years, a senior Western diplomat said.

The blast was certain to increase unease in the foreign community. The U.S. and other western embassies have already instructed diplomats not to bring their children into the country.

“My gut feeling, without much information,” a Western ambassador who declined to be identified said, is that Islamic radicals “are putting pressure on the Western community, the people trying to help Pakistan.”

Police offered no immediate details on how the device was detonated. Officials at the scene said two of those killed were Pakistani security guards.

Danish Foreign Minister Per Stig Moller immediately condemned the attack. “There are fanatics and terrorists out there and we do what we can do protect ourselves from them,” he told Denmark”s TV2 News.

“There”s nothing that indicates that our security measures were inadequate. The Pakistanis have also done more to raise security levels, but a terrorist can slip through all the same. I can”t explain at this moment why this is possible — that”s what I need to find out.”

Helle Thorning-Schmidt, leader of the opposition Social Democrats, called on the Pakistani government to take immediate action. “We expect the Pakistani government to do everything in its power to arrest and to prosecute the guilty ones. The terrorist can not be allowed to get away with their cowardly acts.”

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The Danish Embassy was known to be concerned about its security after Danish newspapers reprinted cartoons satirizing the Prophet Mohammed in February.

In late 2005, Danish newspapers published similar cartoons, sparking widespread street demonstrations in early 2006 in the Middle East and threats of boycotts of Danish products by Muslim countries.

Anxiety among foreigners about security in Islamabad escalated last year after the army assaulted a radical Islamic complex, known as the Red Mosque, killing nearly 100 Islamic militants.

The attack on the mosque provoked intensified round of suicide bomb attacks in Pakistan.

A bomb thrown over the fence of an Italian restaurant in Islamabad on a Saturday night in March when many foreigners were eating on the terrace injured five American employees of the FBI.

That incident caused many foreign embassies to take new precautions and beef up security. The biggest embassies in Islamabad are located in a gated compound reserved entirely for foreign missions. The Danish embassy was several miles from that compound.

The new civilian government in Pakistan is likely to come under increasing pressure from Western governments to pay more attention to the mounting threat from Islamic militants who control much of the nation”s tribal areas.

Until now, the government which was elected in February has spent most of its time arguing about whether to restore 60 judges who were fired by President Pervez Musharraf last November.

The government has agreed to peace deals with the Pakistani Taliban in the tribal region in the last few weeks, a move that has been criticized by the Bush administration on the grounds it gave too much latitude to the militants.

Political observers in Denmark said Monday the bombing would unsettle Danish society, which has found itself under the unwanted spotlight of a perceived culture war between Islam and the West.

“This is almost certain to harden skepticism to radical Islam in the Danish population,” said Ralf Pittelkow, author of a book on Islam and a leading commentator at Jyllands-Posten, the newspaper that provoked the fury of the Muslim world by publishing the cartoons caricaturing the Prophet Muhammad. “People feel shaken by this. It is yet more evidence that we can”t hide from a dangerous world.”

Pittelkow did not expect a violent backlash against Denmark”s Muslim community. But he warned that the recent spurt of Muslim extremism against Denmark — including death threats against the cartoonists who caricatured the prophet — would embolden the far-right Danish People”s Party, which has 13 percent of seats in the Danish Parliament and has pushed through some of the toughest anti-immigration rules on the continent.

He said the Danish government, which has been reaching out to the Muslim world since the cartoon crisis erupted, would likely be redoubling its public diplomacy aimed at dispelling myths about Danish democracy in the Arab countries.

Other commentators said the bombing was not a total surprise, given how Islamists in Pakistan in recent years had seized upon the cartoons as a pretext to express their discontent with the West.

“Islamists in Pakistan had been using Denmark as a pretext for protesting against the new pro-western government,” said Jakob Nielsen, a commentator for Politiken, a leading center-left newspaper. “We have become a convenient scapegoat.”